increasing the heat transfer performance of a ‎turbulator equipped concentric gas-liquid heat ‎exchanger using al2o3 – water nanofluid

In this study, the turbulent fluid flow and heat transfer performance of a concentric two-tube (air-nanofluid) heat exchanger with a helical turbulator is studied using star-ccm+. first, the computational code is validated according to the related experimental data and its simulation results for air and water. then, the heat transfer performance and the effect of the different pitches of the helical turbulators are analyzed by replacing nanofluid instead of water for heat removal. the results show that the turbulator and nanoparticle has a high impact on heat transfer capability of the heat exchanger. the result shows that, the heat transfer is increased using turbulators in comparison with smooth tube for pitches of 15, 30 and 45 mm, respectively. in addition, the star-ccm+ is a proper tool for simulation of a complex geometries in three-dimensional. it is not only the cfd solver, star- ccm+ is an entire engineering process for solving problems involving flow (of fluids or solids), heat transfer and stress. it provides a suite of integrated components that combine to produce a powerful package that can address a wide variety of modeling needs. these components include: • 3d-cad modeler • cad embedding • surface preparation tools • automatic meshing technology • physics models • post-processing